Fig 1: siRNA-mediated knockdown of HEYL suppresses club, goblet and ciliated cell differentiation. HBECs (n = 4 normal, nonsmoker donors) were transfected with either control (siCon) or HEYL (siHEYL) specific siRNA during seeding on ALI culture. On ALI day 7 the cells were harvested for immunofluorescent staining and quantification of (A) basal cells (KRT5, red), (B) intermediate cells (KRT8, red), (C) club cells (SCGB1A1, red), (D) goblet cells (MUC5AC, green) and (E) ciliated cells (FOXJ1). Nuclei are stained blue with DAPI. For each donor, the data are presented as fold-change in cell numbers compared to siCon cells. Scale bar = 20 µm. * p < 0.05.